The whole point of getting units is to break into enemy territory. Otherwise static defenses are better, at least on paper.
Any weird strategy that is more expensive than a cerberus and that can only poke at the front and retreat is not really worth doing, except silos.
Merlins are devastating to unshielded forces and defenses. They can be used to push, doing damage from the safety of range and therefore forcing the enemy to retreat. If you have several merlins and the enemy front is not being pushed back, you're either too far behind in eco to begin with or the merlin was not the correct unit for the given situation.
If you want to use djins, sneak one behind enemy lines (or sneak an athena and build a djin with it) and then have either skuttles take out high cost buildings or warp in a good wave of raiders at once for a surprise attack from the back of the enemy base.
One thing that sounds interesting that I have not yet seen is having a djin in your base make a lamp in the enemy base to provide a safe path of return to an odin. With that said, if the odin made it to its target, it can probably fly back using the same path or it was an intended suicide run that makes cost, so using a djin to recall an odin sounds fancy but it's rarely practical.
I've seen players use djins to recall lances after revealing them to instantly take out a target at the front. That's a good move because the two things a pack of lances fear are bombers swooping in or cloaked raiders suddently popping out of nowhere. If you shoot and reveal your lances and then recall them back to safety while they reload, they can reload moving back to the front and you don't really lose antyhing. That's probably the most practical use of front line djins I have seen so far.
But for the sake of the argument, let's say you have enough merlins to continuously pummel a position. What's the best way of doing that?
You can do a fancy thing with djins, but you can also just use move, force fire at a specific target (all queued) and then turn on repeat. If your move command cover enough distance, the merlins will move in, shoot, move back, move back in and arrive just in time to shoot again.
You can give the exact same commands to several merlins with say 3 second intervals and they will continuously move in, shoot and move out own their own.
I don't see why you would bother to do that. If you have 2+ merlins, you usually have that so you can 1shot static defenses or pierce shields. In both cases, it's better to move all your merlins together at once, have them all shoot at the same location and then move them away.
I don't see how it helps to sustain fire a position when you can burst it instead.
Tremor is awesome for what it does at its cost. It can deplete shields in a large area and it can smoothen the terrain, flattening spires. It absolutely sucks at taking out a single target. Merlins are the exact opposite. They burst and are good at quickly taking something out while the opponent isn't looking, destroying their stuff before they can react if they're not actively paying attention.
